Study on damage deterioration of rock slope under dynamic loads

Abstract

One concern to abrupt failure of rock slope is caused by cumulative damage under dynamic load, and the damage deterioration of rock mass strength is one of the important factors. At the University of Fu Zhou, both laboratory tests and numerical simulation were carried out to study the survival conditions of slope due to the deterioration of geotechnical parameters under dynamic loads. Sandstone fatigue curve and damage evolution rule deduced based on damage mechanics theory could be obtained from fitting the laboratory test data. Relevance between safety factor and fatigue life of rock slope in Sha County was simulated by the finite element method. By means of numerical calculations, the relationship between survival ratio, safety factor and damage factor under dynamic load could be achieved by combining with Weibull distribution function expression of survival ratio and cumulative damage factor. Results show that safety factor of the slope will decrease with its consumption life increasing, and the early changes in safety factor have more sensitivity, it also possessing a middle transition section characteristic before the slope developed to sudden failure; the longer residual life is and the higher safety factor becomes, the greater slope survival ratio will be. Taking the characteristics and median cumulative damage factor as a norm of slope security evaluation respectively, the former indicates that the slope owns a life of more than 35.89 years and its safety factor is greater than 1 but smaller than 3.281; the later means that a higher safety factor is called for meeting the slope survival requirements. Finally, the paper points out that during slope engineering design not just slope safety factor should be considered but also combining safety factor with durability based on the slope sudden failure features and service life requirement.